Video slot machines are slot machines with symbol (graphic) columns in spinning reels, in a mechanical slot machine, implemented with video images. The video slot machines have gained popularity with behaviors of reels and payout patterns that would have been unachievable by mechanical slot machines.
For example, Japanese Patent Application Publication No. 2008-36163 discloses a technique of achieving a wide variety of scatter payouts, based on combinations of symbols in video reels and background colors of the video reels. Japanese Patent Application Publication No. 2015-66396 discloses a technique of implementing the background of a video reel with a second video reel and using graphic, formed for the second video reel, for payout patterns.
Among various aspects that can make the video slot machines distinguishable from other machines and more attractive, a process before the outcome is determined and variation of the payout patterns are of particularly important.